Machine for forming curved surfaces



March 9, 1948- E. o. GARNETT 2,437,596

MACHINE FOR FORMING CURVED SURFACES 2 Sheets-Sheet '1 Filed Aug. 18, 1945 INVENTOR EcZLvcufl Oscar Ga jail-v ATl'ORNE March 9, 1948. o, G R -r 2,437,596

MACHINE FOR FORMING CURVED SURFACES Filed Aug. 18, 1945 2 Sheets-Sheet 2 INVENTOR clwarclosoariarnetk ATTORNEY Patented Mar. 9, i948 MACHINE FOR FORMING CURVED SURFACES Edward Oscar Garnett,

Transvaai, Union of 18, 1945, Serial South Africa May 15, 1945 Application August In the Union of 3 Claims.

This invention relates oving a diamond or like particular to means for curve on the edge of point to out the required grinding wheel.

The object of the invention is to provide a machine embodying a rest for a cutting tool and means for moving the rest and the tool mounted thereon in a predetermined precise circular path. More particularly the object of the invention is to provide a mounting for the tool rest permitting universal sliding motion of the same in one plane and controlling said movement by the limited space occurring between a part having a circle of fixed diameter and an inner circle which can be varied in diameter the difference in the diameters of the two circles limiting the extent of the circular movement of the cutting point of a tool carried by the rest.

A preferred form of the invention is shown in the accompanying drawings in which Fig. l is a perspective view of the device embodying the invention,

Fig. 2 is an elevation of the device partly in section,

Fig. 3 is a plan View with parts centrally located and with parts removed, and

Fig. 4 shows a detail.

In the drawings 5 is a base by which the machine may be clamped in position to cut and dress a grinding wheel. The base supports a pedestal 2 carrying a fixed base 3 having two parallel grooves 4 in which slide fitted pads 5 secured to a plate 1 adapted to slide on base 3 and to carry a tool rest plate 6. Between base 3 and plate 6 is the sliding plate 7 having a pair of parallel grooves a to accommodate sliding pads It secured by screws 9 to tool rest plate Below pads l base plate 3 has two clearance slots l I so that the required movement of pads it is unhampered. The result of said mounting is that tool rest plate 6 may have a limited movement in any direction in one plane. Centrally plate 'i has a circular hole allowing the universal movement desired about a central pin I2 fixed vertically in the pedestal 2. Tool rest plate has a central hole l3 of definite and precise diameter. Over pin l2 and resting on a shoulder I4 is a replaceable disc l5 also of precise diameter. With the parts in position as described the limit of movement of tool rest plate 5 Colbyn, Pretoria,

South Africa is the difierence in the diameters of the disc I5 and the hole 13, or the size of space l6. I1 is a driving plate secured to tool rest plate 6 and having a central circular hole [8. Rotatably mounted on pin 12 is a driving cap l9 and held in place by set screw 20. Said cap l9 has a cylindrical part 2| projecting into but smaller in diameter than hole l8 and having a radially spring loaded plunger 22. The extension 23 of the tool rest plate 6 is adapted to carry the tool 24 in a holder 25. The tool, as shown in the drawings, may be a diamond point 26. Means 21 for rotating the cap l9 may consist of two vertical handles secured to the cap [9.

In operation, rotation of the cap l9 will make the point 26 move through a circle 28, diagrammatically illustrated in Fig. 3, said circle consisting of the four quadrants a, b, c, d. In Fig. 3 is shown a grinding wheel 29 adapted to be rotated by its spindle 39. It is obvious that the quadrant C of the circle 28 can be cut into the edge of the grinding wheel 29 by the diamond point 26 when the rotating wheel 29 is moved towards the point 26 by means for example of the screw 3! and in the slide 32, and when the cap 19 is rotated to move the various parts in the manner above described. Such a movement and setting will give a female curve in the edge of the wheel 29. By setting up the wheel again and oscillating the cap l9 so that the point 26 moves through the quadrant a and suitably adjustting the position of wheel 29 a similar male curve can be cut in the edge of wheel 29. To determine the required movement of point 26 the cap i9 may have a mark 33 thereon which can be made to register with the quadrant marks 34 on the top of the driving plate [1.

The precision of the movement of point 26 and therefore the precision of the work produced by the machine is due to the ease with which the diameter of the replaceable disc I5 is determined.

The machine has been described for use in cutting the desired curves on the edges of grinding wheels. With such wheels the radii 35, 35 (Fig. 4) may be produced on, for example, a punch 31 by the use of wheel 29 in a well known grinding operation.

The invention has been described for use in cutting curves in the edges of grinding wheels but it is obvious that the same machine could be used 3 in a lathe for cutting radii on material mounted therein.

The invention provides a machine by the use of which curves of predetermined size and with precise radii may be cut. The required sizes being controlled by providing easily produced replaceable discs I 5 readily made to the dimensions demanded.

What I claim as new and desire to secure by Letters Patent is:

1. A machine for forming curved surfaces having in combination a tool rest plate, 8.713001 clamp on the plate; a-tool therein, supports for the'plate allowing universal movement thereof in one plane, on said supports, a centrally fixed spindlethreaded through said plate, arcirculan holegof;

precise size in said plate and about the spindles.

a removable disc of a determined, diameter on, said spindle, said disc being smallerinldiamet'e than the circular hole in the tool rest plate, driving means for pressing thatool.restz platezagainstt the disc and for moving it to make-contact round, or partly round the circumference of thadisc, to, provide movement of the point of the toolthrough av circle or a part of a circle restricted in diameter; to; the diiference-in' the -diametersof the -circular, hole inthe toolrest plate: and theremovable disc threadedon the-central spindle;

2; A machine for forming curved surfaceshavingin combination a tool rest-plate, a tool clamp on theplate, a-tool therein; supports ;for-the-plate allowing universal movementthereof inone-plane on said supports, a centrally fixed spindle threaded through said plate, a spring loaded plunger rotatable on the central spindle, a driving plate having a cylinder co-operating with the plunger, said plate being attached to the tool rest plate, means for rotating said plunger, a circular hole of precise size in said tool rest plate and about the spindle, a removable disc of a determined diameter on said spindle, said disc being smaller in diameter than the circular hole in the tool rest plate said rotatable plunger adapted to press the.tooljrest plate against the=disc; and for moving it"to make contact roundor partly round the circumference of the disc to provide movement of the point of the tool through a circle or alpartgofiaicircle restricted in diameter to the difference in the diameters of the circular hole in the tool rest plate and the removable disc threaded'onthecentral spindle.

3: A machine for forming curved surfaces as claimediiniclaim, 1,: characterized in the tool havingia diamond-cutting point.

EDWARD OSCAR GARNETT.

REFERENCES CITED N T STATES BATENTS;

Name Date; Baerer Nov; 19,,1940

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